I have a Protestant friend who is convinced that his Baptist church (not Southern Baptist) is in fact the only “real” Christian church and that they are not Protestants because they are the "original’ church. He bases his belief on the book Trail of Blood by J. M. Carroll. I thought I was pretty good at defending the faith but I’m at a loss on this one. I want to know more about this book and how to refute it, but I don’t know where to find resources. Do you have any information I can turn to?